It's Noc-tan!

Originally designed by @Riakodoadm and given a cameo in a graphic made for the end of GalaxiFEST 2024, she was polished up and properly illustrated by @APPLESdotEXE (shown) in time for Nocturne Rave: Toronto Voyager. Noc-tan has appeared on almost every Nocturne Rave poster since then - although she doesn't get new artwork as often as Galaxi-chan, she still strives to outdo her lighter-haired counterpart in any way she can!

We don't know too much about her origins or personal life, but we can tell you:

Her anniversary is October 5th - on that day in 2024, her full design was first shown to the public on a promotional graphic uploaded not too long before Nocturne Rave: Toronto Voyager
Her Western Zodiac sign is assumed to be Libra...
...both in the traditional 12-sign zodiac, and the 13-sign zodiac including Ophiuchus that was swiftly rejected by society upon discovery
She uses "they/them" pronouns along with "she/her"
Her wings aren't just for show - it seems she really is a demon of some rank
Though she is definitely older than 18, her exact age is unknown - she lists her age as "256" regardless of what year it is
Despite this, she has very clear memories of her childhood from around the 70s and 80s...
...and is still trying to figure out her favorite decade aeshetically - right now, she's into Y2K-ish aesthetics
She is especially fond of 00s goth/raver fashion, and enjoys wearing bright/neon colors on black
Her actual favorite color changes from day to day - sometimes it's bright magenta, sometimes it's sky blue
She frequently comes off as blunt/sardonic, and has problems with having her intentions fully understood by others
She doesn't like the heat of the summer season at all, and much prefers cooler seasons
She seems to know a lot about retro gaming, despite not remembering how to actually play those games - at the moment, she's (re)learning how to play fighting games
She is more into astrology than astronomy
Her sentient teddy bear companion is named Ursa Minor - it often disguises itself as a plush pendant on her belt
She considers Galaxi-chan (the GalaxiFEST mascot) her rival, and competes with her in DJ activities and even gaming - Galaxi-chan is oblivious to this
In the future, she wants to set some time aside for a pro-LGBTQ+ non-profit organization - she's still undecided on a specific cause